I believe opinions are fine to have, the problem comes with tone, like this thread suggests. The issue comes when someone tries to push their opinion on others. Like religion and politics this is nothing but trouble when you approach it like this. Others Will disagree with an opinion and will state their own as a response every single time. Undead asked if a color blind person was wrong for saying grass is green, that is not completely false because he is presenting his point of view. It's when someone brings a counter argument, like he should remember he is color blind so he is missing a portion of the facts, and he still insists his opinions are absolute.
I see online many people trying to insist that the Earth is actually flat because they don't see the roundness. That is an argument based on little to no facts and is just an Ideology (i.e. and opinion) and when presented with a counter argument suggesting the world is round and evidence supports this as a truth is the Flat Earth still a viable opinion? And is it right when they insult everyone who questions them as being mislead sheep? Should the pro-round group back down and say their opinion is as valid as the proof that says otherwise?
The tone has absolutely gotten out of control and I was apart of that, but step back and let's admit opinions are fine but there is definitely a line when an opinion should just be stopped being expressed because it is poisonous logic. I can't turn back my knowledge and say Flat Earthers could be right because they have an opinion because they are just plain wrong. Now are the current complaints wrong? So far the evidence seems to favor one side but it is still local regions subjective. So it's not 100% either way, but there is no reason to start the fight in the first place. People are naturally defensive and it takes a lot of effort not to be. So don't start an aggressive argument with insults in the first place.